An international team of Earth and environmental scientists has found evidence that the Ronne Ice Shelf in the West Antarctic did not melt during the last interglacial event, suggesting it could survive modern climate change. In their study published in the journal Nature, the team analyzed ice core samples taken from a site near the shelf’s edge. The editors at Nature have also published a Research Briefing summarizing the work.

Environmental scientists have been studying the Ronne Ice Shelf due to its massive size. Prior research has suggested that if it were to break away from the ice cap and melt, the result would be a global rise in sea levels as high as 2 meters—more than enough to flood multiple coastal metropolitan areas around the world.

For their new study, the researchers drilled and removed an ice core down to the level of bedrock (651 meters deep) at Skytrain Ice Rise, near the edge of the Ronne Ice Shelf. Their thinking was that if the ice shelf had melted the last time the planet experienced higher-than-normal temperatures (due to changes in Earth’s orbit), there would be significantly higher concentrations of sea salt near its edges because it extends out over the water.

But instead of higher concentrations of sea salt, the research team found them to be the same as other parts of the shelf or even lower, suggesting the shelf had not undergone much, if any, melting. The team also tested for isotopes that carry evidence of weather events in the ice, and found no evidence that the shelf had undergone significant melting.

The researchers suggest that the Ronne Ice Shelf is not likely to melt under current conditions, or even if the planet grows warmer. But they also note that some conditions are different today than they were during the last global warming—ocean temperatures are warmer, which means the shelf could undergo melting below the surface, which, if combined with increased temperatures above, could lead to a different outcome.

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